Tag: Lockheed C-5 Page 1 of 2

Adventures on the Air Refueling Track

On February 23, 2009

The last two posts covered all the procedural steps necessary to accomplish an air refueling mission or qualification. Completing an AR mission is an exercise in flying formation with another aircraft, specifically in close trail formation. Just as in any other formation flying, maintaining position involves recognizing relative movement between the airplanes and managing the momentum of aircraft movement. Obviously, the bigger the airplane, the more momentum is involved. I was also an instructor in the USAF Undergraduate Pilot Training (UPT) program, teaching in the Cessna T-37, a small, 2-seat jet. Formation training was part of the flight syllabus and was usually the first time that the student had the opportunity to get close to another aircraft in flight. The skill sets required to fly formation in the T-37 and to air refuel in the C-5 are very similar, though with the C-5 you have to be more patient with power changes. The C-5’s flight controls are quick for an aircraft of it’s size and the engines are powerful enough that power changes, once in position, rarely require more movement than 1/2 to 3/4 throttle knob width. Pilots new to air refueling or to formation flying in general have a tendency to make corrections that last too long. When in close proximity to another aircraft heading changes of one or two degrees are all that are needed to see movement. You have to make a concerted effort to barely change bank angle and then level the wings again to make a lateral position correction. Just a little rotational pressure on the yolk is used rather than actually rotating it to see a bank angle change. Power changes need time to take effect. If you get impatient and make an additional power correction before the first one has time to take effect, you end up with at least twice the power change that you need. Soon you find yourself fighting your own corrections.

I spent most of my last four years in the Air Force teaching or evaluating pilots while air refueling. Most of the missions were fairly routine, but every once in a while we’d have an interesting time trying to complete a training mission.

Aviation History – Air Refueling the C-5, Part 2

By Tracy

On February 20, 2009

In Military Flying

This is the second half of a 2-part post on air refueling the Lockheed C-5. Part 1 of Air Refueling the Lockheed C-5 may be found here.

Air Refueling the C-5, Moving In

We left off with the receiver in the pre-contact position with both aircraft ready to conduct air refueling. At this point, the boom operator is looking at something like this.You can see the air refueling receptacle just aft of the cockpit with the white lead-in strips to help the boom operator. The refueling door is open.

There is a centerline stripe painted on the bottom of the tanker to help with alignment as you move into the contact position. The boom operator “flies” the boom with the two wings shown in the photo, moving it left or right and up and down through an arc. The inner portion of boom telescopes out to press into the refueling receptacle.

The bottom of the tanker has two rows of indicator lights, one on either side of the centerline stripe. In the photos they look like dark bars. These lights provide an indication of the receiver position with respect to the ideal refueling position. There is a “box” of airspace that the receiver must remain within. The box dimensions are determined by the lateral and vertical limits of movement of the refueling boom and the limits of the extension and retraction of the inner portion of the boom. If you are the refueling pilot and sitting in the left seat it is easy to think of the left row of indicator lights being controlled by your left hand (the yolk moving the aircraft up or down) and the right row of lights being controlled by your right hand (throttle moving the aircraft forward or aft). This is not completely true, of course, because the arc movement of the boom means a movement forward will not only compress the boom, but cause it to move downward in the arc. It is a good generalization, though. As I remember, each end of the light bar (forward and aft) has a red light, meaning you are nearing a disconnect. Then there are three or four amber lights on each side of a center green light. The center of the refueling envelope is attained when you have two green lights illuminated, one on each set of lights. Until the boom is latched into the refueling receptacle, the indicator lights are manually controlled by the boom operator.

Aviation History – Air Refueling the C-5, Part 1

By Tracy

On February 18, 2009

In Military Flying

I had originally intended to post a single article on Lockheed C-5 air refueling, but I have been typing away and see that it is way too long for a single post, so I’ll break it up into two parts. Part 2 will be up in two days.

Air Refueling Procedures

Before we get into the specifics of air refueling a C-5, let’s figure out how the two airplanes find each other and arrive in a position to refuel. The C-5 is intended to be loaded up with the cargo to be moved, then fueled to reach the intended destination or to attain the maximum takeoff weight. Boeing KC-135 and Lockheed C-5 Air Refueling. If the amount of fuel boarded is not enough to complete the flight, an air refueling mission is planned. When an air refueling mission is required, an air refueling track is reserved and a tanker (either a KC-135 or a KC-10) is assigned to the mission. Air refueling tracks are mini-airways set aside for military use for refueling missions. The military flight planning publications list all of refueling tracks, the altitudes that are available and what agency controls them. Click on the photo to see it large enough to read the information. There are several column labels across the top that we’ll talk a little about. (There is no telling the age of this air refueling track information. Do I need to put a label on it saying “Not For Navigation Purposes” ?)

The first column gives the track identifier. Let’s look at AR106L (East). The next four columns are navigation points that define the track. If you were to plot them on a chart they would define a relatively straight line starting near Hill City, KS and ending east of Rapid City, SD. The column ARIP is the Air Refueling Initial Point, ARCP is the Air Refueling Contact Point. and the other two labels are self-explanatory. CR Plan is the Communications/Rendezvous Plan and references setting for the communications and identification equipment found on the respective aircraft. The remaining columns list the altitudes available, who schedules the track and who handles air traffic control of the aircraft on the track. There is also an ARCT involved with the operation which is not listed. The Air Refueling Contact Time is the time both aircraft are to be at the ARCP. It is established when the track is reserved. (Enough letters for you?)

Ramblings about flying for fun and profit.